custom firmware is the best (IMO)because it gives you the ability to play homebrew and downloaded games, and is still up to date firmware-no need for emulation..The latest is 3.40OE-A, although some people say that the lower custom firmwares are a little better because they have been revised and had a chance to get the bugs worked out...The original version or sony official firmware on the other hand, does not allow playing homebrew and downloaded games-they want you to drop your hard-earned cash on those little UMD discs at $15-40 a pop...not good.